package org.apache.log4j;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.File;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.Writer;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;

import org.apache.log4j.DailyRollingFileAppender;
import org.apache.log4j.FileAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.CountingQuietWriter;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.spi.LoggingEvent;

/**
 * DailyRollingFileAppender extends {@link FileAppender} so that the underlying
 * file is rolled over at a user chosen frequency.
 * 
 * DailyRollingFileAppender has been observed to exhibit synchronization issues
 * and data loss. The log4j extras companion includes alternatives which should
 * be considered for new deployments and which are discussed in the
 * documentation for org.apache.log4j.rolling.RollingFileAppender.
 * 
 * <p>
 * The rolling schedule is specified by the <b>DatePattern</b> option. This
 * pattern should follow the {@link SimpleDateFormat} conventions. In
 * particular, you <em>must</em> escape literal text within a pair of single
 * quotes. A formatted version of the date pattern is used as the suffix for the
 * rolled file name.
 * 
 * <p>
 * For example, if the <b>File</b> option is set to <code>/foo/bar.log</code>
 * and the <b>DatePattern</b> set to <code>'.'yyyy-MM-dd</code>, on 2001-02-16
 * at midnight, the logging file <code>/foo/bar.log</code> will be copied to
 * <code>/foo/bar.log.2001-02-16</code> and logging for 2001-02-17 will continue
 * in <code>/foo/bar.log</code> until it rolls over the next day.
 * 
 * <p>
 * Is is possible to specify monthly, weekly, half-daily, daily, hourly, or
 * minutely rollover schedules.
 * 
 * <p>
 * <table border="1" cellpadding="2">
 * <tr>
 * <th>DatePattern</th>
 * <th>Rollover schedule</th>
 * <th>Example</th>
 * 
 * <tr>
 * <td><code>'.'yyyy-MM</code>
 * <td>Rollover at the beginning of each month</td>
 * 
 * <td>At midnight of May 31st, 2002 <code>/foo/bar.log</code> will be copied to
 * <code>/foo/bar.log.2002-05</code>. Logging for the month of June will be
 * output to <code>/foo/bar.log</code> until it is also rolled over the next
 * month.
 * 
 * <tr>
 * <td><code>'.'yyyy-ww</code>
 * 
 * <td>Rollover at the first day of each week. The first day of the week depends
 * on the locale.</td>
 * 
 * <td>Assuming the first day of the week is Sunday, on Saturday midnight, June
 * 9th 2002, the file <i>/foo/bar.log</i> will be copied to
 * <i>/foo/bar.log.2002-23</i>. Logging for the 24th week of 2002 will be output
 * to <code>/foo/bar.log</code> until it is rolled over the next week.
 * 
 * <tr>
 * <td><code>'.'yyyy-MM-dd</code>
 * 
 * <td>Rollover at midnight each day.</td>
 * 
 * <td>At midnight, on March 8th, 2002, <code>/foo/bar.log</code> will be copied
 * to <code>/foo/bar.log.2002-03-08</code>. Logging for the 9th day of March
 * will be output to <code>/foo/bar.log</code> until it is rolled over the next
 * day.
 * 
 * <tr>
 * <td><code>'.'yyyy-MM-dd-a</code>
 * 
 * <td>Rollover at midnight and midday of each day.</td>
 * 
 * <td>At noon, on March 9th, 2002, <code>/foo/bar.log</code> will be copied to
 * <code>/foo/bar.log.2002-03-09-AM</code>. Logging for the afternoon of the 9th
 * will be output to <code>/foo/bar.log</code> until it is rolled over at
 * midnight.
 * 
 * <tr>
 * <td><code>'.'yyyy-MM-dd-HH</code>
 * 
 * <td>Rollover at the top of every hour.</td>
 * 
 * <td>At approximately 11:00.000 o'clock on March 9th, 2002,
 * <code>/foo/bar.log</code> will be copied to
 * <code>/foo/bar.log.2002-03-09-10</code>. Logging for the 11th hour of the 9th
 * of March will be output to <code>/foo/bar.log</code> until it is rolled over
 * at the beginning of the next hour.
 * 
 * 
 * <tr>
 * <td><code>'.'yyyy-MM-dd-HH-mm</code>
 * 
 * <td>Rollover at the beginning of every minute.</td>
 * 
 * <td>At approximately 11:23,000, on March 9th, 2001, <code>/foo/bar.log</code>
 * will be copied to <code>/foo/bar.log.2001-03-09-10-22</code>. Logging for the
 * minute of 11:23 (9th of March) will be output to <code>/foo/bar.log</code>
 * until it is rolled over the next minute.
 * 
 * </table>
 * 
 * <p>
 * Do not use the colon ":" character in anywhere in the <b>DatePattern</b>
 * option. The text before the colon is interpeted as the protocol specificaion
 * of a URL which is probably not what you want.
 * 
 * @author Eirik Lygre
 * @author Ceki G&uuml;lc&uuml;
 */
public class LimitDailyRollingFileAppender extends FileAppender {

	// The code assumes that the following constants are in a increasing
	// sequence.
	static final int TOP_OF_TROUBLE = -1;
	static final int TOP_OF_MINUTE = 0;
	static final int TOP_OF_HOUR = 1;
	static final int HALF_DAY = 2;
	static final int TOP_OF_DAY = 3;
	static final int TOP_OF_WEEK = 4;
	static final int TOP_OF_MONTH = 5;

	/**
	 * The date pattern. By default, the pattern is set to "'.'yyyy-MM-dd"
	 * meaning daily rollover.
	 */
	private String datePattern = "'.'yyyy-MM-dd";

	/**
	 * The log file will be renamed to the value of the scheduledFilename
	 * variable when the next interval is entered. For example, if the rollover
	 * period is one hour, the log file will be renamed to the value of
	 * "scheduledFilename" at the beginning of the next hour.
	 * 
	 * The precise time when a rollover occurs depends on logging activity.
	 */
	private String scheduledFilename;
	private String originalFilename;

	/**
	 * The next time we estimate a rollover should occur.
	 */
	private long nextCheck = System.currentTimeMillis() - 1;

	Date now = new Date();

	SimpleDateFormat sdf;

	RollingXCalendar rc = new RollingXCalendar();

	int checkPeriod = TOP_OF_TROUBLE;

	// The gmtTimeZone is used only in computeCheckPeriod() method.
	static final TimeZone gmtTimeZone = TimeZone.getTimeZone("GMT");

	/**
	 * The default constructor does nothing.
	 */
	public LimitDailyRollingFileAppender() {
	}

	/**
	 * Instantiate a <code>DailyRollingFileAppender</code> and open the file
	 * designated by <code>filename</code>. The opened filename will become the
	 * ouput destination for this appender.
	 */
	public LimitDailyRollingFileAppender(Layout layout, String filename,
			String datePattern, int maxFileSize, int maxBackupIndex)
			throws IOException {
		super(layout, filename, true);
		this.datePattern = datePattern;
		this.maxFileSize = maxFileSize;
		this.maxBackupIndex = maxBackupIndex;
		activateOptions();
	}

	/**
	 * The <b>DatePattern</b> takes a string in the same format as expected by
	 * {@link SimpleDateFormat}. This options determines the rollover schedule.
	 */
	public void setDatePattern(String pattern) {
		datePattern = pattern;
	}

	/** Returns the value of the <b>DatePattern</b> option. */
	public String getDatePattern() {
		return datePattern;
	}

	public void activateOptions() {
		super.activateOptions();
		if (datePattern != null && fileName != null) {
			now.setTime(System.currentTimeMillis());
			sdf = new SimpleDateFormat(datePattern);
			int type = computeCheckPeriod();
			printPeriodicity(type);
			rc.setType(type);
			File file = new File(fileName);
			scheduledFilename = fileName + sdf.format(new Date(file.lastModified()));
			originalFilename = fileName;

		} else {
			LogLog.error("Either File or DatePattern options are not set for appender ["
					+ name + "].");
		}
	}

	void printPeriodicity(int type) {
		switch (type) {
		case TOP_OF_MINUTE:
			LogLog.debug("Appender [" + name + "] to be rolled every minute.");
			break;
		case TOP_OF_HOUR:
			LogLog.debug("Appender [" + name
					+ "] to be rolled on top of every hour.");
			break;
		case HALF_DAY:
			LogLog.debug("Appender [" + name
					+ "] to be rolled at midday and midnight.");
			break;
		case TOP_OF_DAY:
			LogLog.debug("Appender [" + name + "] to be rolled at midnight.");
			break;
		case TOP_OF_WEEK:
			LogLog.debug("Appender [" + name
					+ "] to be rolled at start of week.");
			break;
		case TOP_OF_MONTH:
			LogLog.debug("Appender [" + name
					+ "] to be rolled at start of every month.");
			break;
		default:
			LogLog.warn("Unknown periodicity for appender [" + name + "].");
		}
	}

	// This method computes the roll over period by looping over the
	// periods, starting with the shortest, and stopping when the r0 is
	// different from from r1, where r0 is the epoch formatted according
	// the datePattern (supplied by the user) and r1 is the
	// epoch+nextMillis(i) formatted according to datePattern. All date
	// formatting is done in GMT and not local format because the test
	// logic is based on comparisons relative to 1970-01-01 00:00:00
	// GMT (the epoch).

	int computeCheckPeriod() {
		RollingXCalendar RollingXCalendar = new RollingXCalendar(gmtTimeZone,
				Locale.getDefault());
		// set sate to 1970-01-01 00:00:00 GMT
		Date epoch = new Date(0);
		if (datePattern != null) {
			for (int i = TOP_OF_MINUTE; i <= TOP_OF_MONTH; i++) {
				SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
						datePattern);
				simpleDateFormat.setTimeZone(gmtTimeZone); // do all date
				// formatting in GMT
				String r0 = simpleDateFormat.format(epoch);
				RollingXCalendar.setType(i);
				Date next = new Date(RollingXCalendar.getNextCheckMillis(epoch));
				String r1 = simpleDateFormat.format(next);
				// System.out.println("Type = "+i+", r0 = "+r0+", r1 = "+r1);
				if (r0 != null && r1 != null && !r0.equals(r1)) {
					return i;
				}
			}
		}
		return TOP_OF_TROUBLE; // Deliberately head for trouble...
	}

	/**
	 * Original DailyRollingFileAppender logic Rollover the current file to a
	 * new file.
	 */
	void rollOver() throws IOException {

		/* Compute filename, but only if datePattern is specified */
		if (datePattern == null) {
			errorHandler.error("Missing DatePattern option in rollOver().");
			return;
		}

		String datedFilename = fileName + sdf.format(now);
		// It is too early to roll over because we are still within the
		// bounds of the current interval. Rollover will occur once the
		// next interval is reached.
		if (scheduledFilename.equals(datedFilename)) {
			return;
		}

		// close current file, and rename it to datedFilename
		this.closeFile();

		File target = new File(scheduledFilename);
		if (target.exists()) {
			target.delete();
		}

		File file = new File(fileName);
		boolean result = file.renameTo(target);
		if (result) {
			LogLog.debug(fileName + " -> " + scheduledFilename);
		} else {
			LogLog.error("Failed to rename [" + fileName + "] to ["
					+ scheduledFilename + "].");
		}

		try {
			// This will also close the file. This is OK since multiple
			// close operations are safe.
			this.setFile(fileName, true, this.bufferedIO, this.bufferSize);
		} catch (IOException e) {
			errorHandler.error("setFile(" + fileName + ", true) call failed.");
		}
		scheduledFilename = datedFilename;
	}

	/**
	 * This method differentiates DailyRollingFileAppender from its super class.
	 * 
	 * <p>
	 * Before actually logging, this method will check whether it is time to do
	 * a rollover. If it is, it will schedule the next rollover time and then
	 * rollover.
	 * */
	protected void subAppend(LoggingEvent event) {
		long n = System.currentTimeMillis();
		if (n >= nextCheck) {
			now.setTime(n);
			nextCheck = rc.getNextCheckMillis(now);
			try {
				rollOver();

			} catch (IOException ioe) {
				if (ioe instanceof InterruptedIOException) {
					Thread.currentThread().interrupt();
				}
				LogLog.error("rollOver() failed.", ioe);
			}
		}
		
		if (fileName != null && qw != null) {
			long size = ((CountingQuietWriter) qw).getCount();
			if (size >= maxFileSize && size >= nextRollover) {
				rollOver1();
			}
		}

		super.subAppend(event);

	}

	/*
	 * Newly add things
	 */

	/**
	 * The default maximum file size is 10MB.
	 */
	protected long maxFileSize = 10 * 1024 * 1024;

	/**
	 * There is one backup file by default.
	 */
	protected int maxBackupIndex = 1;

	private long nextRollover = 0;

	/**
	 * Returns the value of the <b>MaxBackupIndex</b> option.
	 */
	public int getMaxBackupIndex() {
		return maxBackupIndex;
	}

	/**
	 * Get the maximum size that the output file is allowed to reach before
	 * being rolled over to backup files.
	 * 
	 * @since 1.1
	 */
	public long getMaximumFileSize() {
		return maxFileSize;
	}

	/**
	 * Set the maximum number of backup files to keep around.
	 * 
	 * <p>
	 * The <b>MaxBackupIndex</b> option determines how many backup files are
	 * kept before the oldest is erased. This option takes a positive integer
	 * value. If set to zero, then there will be no backup files and the log
	 * file will be truncated when it reaches <code>MaxFileSize</code>.
	 */
	public void setMaxBackupIndex(int maxBackups) {
		this.maxBackupIndex = maxBackups;
	}

	/**
	 * Set the maximum size that the output file is allowed to reach before
	 * being rolled over to backup files.
	 * 
	 * <p>
	 * This method is equivalent to {@link #setMaxFileSize} except that it is
	 * required for differentiating the setter taking a <code>long</code>
	 * argument from the setter taking a <code>String</code> argument by the
	 * JavaBeans {@link java.beans.Introspector Introspector}.
	 * 
	 * @see #setMaxFileSize(String)
	 */
	public void setMaximumFileSize(long maxFileSize) {
		this.maxFileSize = maxFileSize;
	}

	/**
	 * Set the maximum size that the output file is allowed to reach before
	 * being rolled over to backup files.
	 * 
	 * <p>
	 * In configuration files, the <b>MaxFileSize</b> option takes an long
	 * integer in the range 0 - 2^63. You can specify the value with the
	 * suffixes "KB", "MB" or "GB" so that the integer is interpreted being
	 * expressed respectively in kilobytes, megabytes or gigabytes. For example,
	 * the value "10KB" will be interpreted as 10240.
	 */
	public void setMaxFileSize(String value) {
		maxFileSize = OptionConverter.toFileSize(value, maxFileSize + 1);
	}

	protected void setQWForFiles(Writer writer) {
		this.qw = new CountingQuietWriter(writer, errorHandler);
	}

	public synchronized void setFile(String fileName, boolean append,
			boolean bufferedIO, int bufferSize) throws IOException {
		super.setFile(fileName, append, this.bufferedIO, this.bufferSize);
		if (append) {
			File f = new File(fileName);
			((CountingQuietWriter) qw).setCount(f.length());
		}
	}

	// Original RollingFileDailyAppender rollover logic
	public// synchronization not necessary since doAppend is alreasy synched
	void rollOver1() {
		File target;
		File file;
		
		String tempFileName = originalFilename + sdf.format(now);

		if (qw != null) {
			long size = ((CountingQuietWriter) qw).getCount();
			LogLog.debug("rolling over count=" + size);
			// if operation fails, do not roll again until
			// maxFileSize more bytes are written
			nextRollover = size + maxFileSize;
		}
		LogLog.debug("maxBackupIndex=" + maxBackupIndex);

		boolean renameSucceeded = true;
		// If maxBackups <= 0, then there is no file renaming to be done.
		if (maxBackupIndex > 0) {
			// Delete the oldest file, to keep Windows happy.
			file = new File(tempFileName + '.' + maxBackupIndex);
			if (file.exists())
				renameSucceeded = file.delete();

			// Map {(maxBackupIndex - 1), ..., 2, 1} to {maxBackupIndex, ..., 3,
			// 2}
			for (int i = maxBackupIndex - 1; i >= 1 && renameSucceeded; i--) {
				file = new File(tempFileName + "." + i);
				if (file.exists()) {
					target = new File(tempFileName + '.' + (i + 1));
					LogLog.debug("Renaming file " + file + " to " + target);
					renameSucceeded = file.renameTo(target);
				}
			}

			if (renameSucceeded) {
				// Rename fileName to fileName.1
				target = new File(tempFileName + "." + 1);

				this.closeFile(); // keep windows happy.

				file = new File(tempFileName);
				LogLog.debug("Renaming file " + file + " to " + target);
				renameSucceeded = file.renameTo(target);
				//
				// if file rename failed, reopen file with append = true
				//
				if (!renameSucceeded) {
					try {
						this.setFile(tempFileName, true, bufferedIO, bufferSize);
					} catch (IOException e) {
						LogLog.error("setFile(" + tempFileName + ", true) call failed.", e);
					}
				}
			}
		}

		//
		// if all renames were successful, then
		//
		if (renameSucceeded) {
			try {
				// This will also close the file. This is OK since multiple
				// close operations are safe.
				this.setFile(tempFileName, false, bufferedIO, bufferSize);
				nextRollover = 0;
			} catch (IOException e) {
				LogLog.error("setFile(" + tempFileName + ", false) call failed.", e);
			}
		}
	}
}

/**
 * RollingXCalendar is a helper class to DailyRollingFileAppender. Given a
 * periodicity type and the current time, it computes the start of the next
 * interval.
 * */
class RollingXCalendar extends GregorianCalendar {
	private static final long serialVersionUID = -3560331770601814177L;

	int type = LimitDailyRollingFileAppender.TOP_OF_TROUBLE;

	RollingXCalendar() {
		super();
	}

	RollingXCalendar(TimeZone tz, Locale locale) {
		super(tz, locale);
	}

	void setType(int type) {
		this.type = type;
	}

	public long getNextCheckMillis(Date now) {
		return getNextCheckDate(now).getTime();
	}

	public Date getNextCheckDate(Date now) {
		this.setTime(now);

		switch (type) {
		case LimitDailyRollingFileAppender.TOP_OF_MINUTE:
			this.set(Calendar.SECOND, 0);
			this.set(Calendar.MILLISECOND, 0);
			this.add(Calendar.MINUTE, 1);
			break;
		case LimitDailyRollingFileAppender.TOP_OF_HOUR:
			this.set(Calendar.MINUTE, 0);
			this.set(Calendar.SECOND, 0);
			this.set(Calendar.MILLISECOND, 0);
			this.add(Calendar.HOUR_OF_DAY, 1);
			break;
		case LimitDailyRollingFileAppender.HALF_DAY:
			this.set(Calendar.MINUTE, 0);
			this.set(Calendar.SECOND, 0);
			this.set(Calendar.MILLISECOND, 0);
			int hour = get(Calendar.HOUR_OF_DAY);
			if (hour < 12) {
				this.set(Calendar.HOUR_OF_DAY, 12);
			} else {
				this.set(Calendar.HOUR_OF_DAY, 0);
				this.add(Calendar.DAY_OF_MONTH, 1);
			}
			break;
		case LimitDailyRollingFileAppender.TOP_OF_DAY:
			this.set(Calendar.HOUR_OF_DAY, 0);
			this.set(Calendar.MINUTE, 0);
			this.set(Calendar.SECOND, 0);
			this.set(Calendar.MILLISECOND, 0);
			this.add(Calendar.DATE, 1);
			break;
		case LimitDailyRollingFileAppender.TOP_OF_WEEK:
			this.set(Calendar.DAY_OF_WEEK, getFirstDayOfWeek());
			this.set(Calendar.HOUR_OF_DAY, 0);
			this.set(Calendar.MINUTE, 0);
			this.set(Calendar.SECOND, 0);
			this.set(Calendar.MILLISECOND, 0);
			this.add(Calendar.WEEK_OF_YEAR, 1);
			break;
		case LimitDailyRollingFileAppender.TOP_OF_MONTH:
			this.set(Calendar.DATE, 1);
			this.set(Calendar.HOUR_OF_DAY, 0);
			this.set(Calendar.MINUTE, 0);
			this.set(Calendar.SECOND, 0);
			this.set(Calendar.MILLISECOND, 0);
			this.add(Calendar.MONTH, 1);
			break;
		default:
			throw new IllegalStateException("Unknown periodicity type.");
		}
		return getTime();
	}
}